The present invention relates to a device for conditioning hydrosoluble fertilizers and/or other hydrosoluble products usable in agriculture, in pisciculture for the treatment of diseases, disinfection, the supply of nutrients, etc., as well as the treatment of ornamental lakes (fungicides, disinfectants), which makes it possible to obtain a programmed desorption of the fertilizers and/or products in the medium to be fertilized or treated.
For some years now research has been directed at providing delayed action fertilizers, which can be progressively released into the medium to be fertilized. This research has led to the production of concentrated granular fertilizers in which around the very small fertilizer granules are formed one or more coatings based on hydrophobic materials, such as soya alkyd resins and phenol formaldehyde resins. French Pat. Nos. 1 279 110 and 1 419 969 illustrate the preparation of such products by spraying finishing coatings and complementary coatings on to fertilizer granules or powder. This procedure makes it possible to influence the speed of release of the fertilizer by appropriately choosing the number and nature of the different coatings which are successively applied. However, it is difficult to regulate to an appropriate value and for an extended time the amount of fertilizer which is released. Moreover, the preparation of these products necessitates complex installations and is difficult to realize.